Some great books and guides on Keyword Optimization.
Search Engine Optimization (SEO) Secrets
Tips, tricks, and
little-known methods used by professional SEO consultants to rank in
some of the most competitive search phrases
Amazon Price: $18.46 (as of 10/04/2012) 
Search Engine Optimization All-in-One For Dummies (For Dummies (Business & Personal Finance))
Ten minibooks cover all you need to know about search engine optimization
Amazon Price: $21.32 (as of 10/04/2012)
Website Optimization: Speed, Search Engine & Conversion Rate Secrets
This book is a comprehensive guide to the tips, techniques, secrets, standards, and methods of website optimization
Amazon Price: $22.00 (as of 10/04/2012)
Optimize: How to Attract and Engage More Customers by Integrating SEO, Social Media, and Content Marketing
Attract, engage, and inspire your customers with an "Optimize and Socialize" content marketing strategy
Amazon Price: $13.12 (as of 10/04/2012)
The Art of SEO
brings you up to
date on recent changes in search engine behavior-such as new ranking
methods involving user engagement and social media-with an array of
effective tactics, from basic to advanced.
Amazon Price: $34.77 (as of 10/04/2012)